Investigation of influence of 16-slice spiral CT electrocardiogram-controlled dose modulation on exposure dosage and image quality of cardiac CT imaging under simulated fluctuant heart rate
- VernacularTitle:16层CT心电图调制电流对有心率波动的心脏CT扫描曝光剂量及图像质量影响
- Author:
Yan YIN
;
Jie CHEN
;
Weiming CHAI
;
Jia HUA
;
Yun SHEN
;
Na GAO
;
Jiantong XU
- Publication Type:Journal Article
- Keywords:
Heart rate;
Coronary vessels;
Tomography,X-ray computed;
Quality control
- From:
Chinese Journal of Radiology
2008;42(10):1035-1039
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the influence of electrocardiogram(ECG)-controlled dose modulation on exposure dosage and image quality of cardiac CT imaging in a cardiac phantom with simulated fluctuant heart rate.Methods The basal heart rate of the cardiac pulsating phantom was set as 60 bpm.the experimental situations were divided as 6 groups according to different heart rates.The cardiac imaging was performed on the cardiac phantom when the ECG-controlled dose modulation was firstly turned off.The exposure dosage of each scan sequence was documented.The standard deviation of the CT values of the phantom was measured on the central slice after coronal reformation of the raw data.The quality of 2D and 3D images were scored.Thell cardiac imaging was performed when ECG modulation was on and set as four groups according to different modulation parameters.All the data were documented as before.The results from the five groups with and without ECG modulation current were analyzed bv F test and comparative rank sum test using the statistical software SPSS 10.0.Results Statistical analysis showed no significant difference(P＞0.05)between the SNR of images(SD value was 27.78 and 26.30)from the groups that full mA output at wide reconstruction phase(69%～99%)when the heart rate was fluctuant(≥7.5 bpm).There was also no significant difference(P＞0.05)between the quality of the 2D and 3D images.But there was a significant difference(P＜0.01)between the SNR of images(SD value was 26.78 and 29.90)that full mA was only used at 85%reconstruction phase when the heart rate Was fluctuant(≥7.5 bpm).The exposure dosage was remarkably reduced when the ECG modulated current was on than when it Was off under fluctuant heart rate.Furthermore.there were significant difierence(P＜0.01)among the difierent ECG modulated current parameter groups.The exposure dosage can be reduced by 44.7%under the situation that the heart rate was fluctuant.Whell the fluctuation of the heart rate was≤12.5 bpm,there wag no obvious relationship between the fluctuation of the heart rate and the exposure dosage (the variation was from 0.1 to 1.1 mSv),but if the heart rate fluctuation was＞12.5 bpm,the exposure dosage would increase obviously (from 0.6 to 1.7 mSv).Conclusion For cardiac imaging with 16-slice row CT,the application of ECG modulated current can effectively reduce the exposure dosage without compromising the image quality even if heart rate was fluctuant.
